9.2.5 LEFT SEMI JOIN.............................................................................................23
9.2.6 MAP SIDE JOIN...............................................................................................23
9.3 Order by, Sort by ,Dristribute by,Cluster By .........................................24
9.3.1 order by ........................................................................................................24
9.3.2 sort by ..........................................................................................................24
9.3.3 distribute by...............................................................................................24
9.3.4 Cluster By ....................................................................................................25
10 HiveQL:视图 ..................................................................................................................25
10.1 创建 View ...............................................................................................................25
10.2 删除 view ...............................................................................................................25
10.3 修改 view ...............................................................................................................25
11 HiveQL:索引 ..................................................................................................................26
11.1 创建索引： ............................................................................................................26
11.2 重建索引： ............................................................................................................27
11.3 删除索引 ................................................................................................................27
12 Hive 元数据 ...................................................................................................................27
12.1 数据字典 ................................................................................................................27
13 数据倾斜 ........................................................................................................................28
13.1 数据倾斜的原因 ....................................................................................................28
13.1.1 操作 ........................................................................................................28
13.1.2 原因 ........................................................................................................28
13.1.3 表现 ........................................................................................................28
13.2 数据倾斜的解决方案.............................................................................................29
13.2.1 参数调节.................................................................................................29
13.2.2 SQL 语句调节..........................................................................................29
13.2.3 空值产生的数据倾斜.............................................................................29
13.3 不同数据类型关联产生数据倾斜.........................................................................30
13.3.1 小表不小不大，怎么用 map join 解决倾斜问题 .............................30
13.4 总结 ........................................................................................................................31
14 Hive 参数优化 ...............................................................................................................31
14.1 本地模式(小任务).................................................................................................31
14.2 并发执行 ................................................................................................................31
14.3 Strict Mode ..........................................................................................................32
14.4 动态分区： ............................................................................................................32
14.5 推测执行： ............................................................................................................32
14.6 Single MapReduce MultiGROUP BY.....................................................................32
14.7 是否提供虚拟列 ....................................................................................................32
14.8 分组 ........................................................................................................................32
14.9 Map 端部分聚合 ....................................................................................................33
14.10 Multi- Group-By Inserts ..........................................................................................33
14.11 排序 ........................................................................................................................33
14.12 合并小文件 ............................................................................................................33
14.13 Map/reduce 数目 ...................................................................................................34
15 常用优化方向 ................................................................................................................34
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